Calendula in Zone 10A — Florida

Calendula is a fantastic addition to any Florida garden. Its bright, cheerful flowers are not just pretty; the petals are edible, adding a peppery zing to salads, and have medicinal properties. Plus, growing your own means you can enjoy fresh, organic calendula without the grocery store markup.

While Florida's heat and humidity can be challenging, our long growing season makes it possible to enjoy calendula. By planting in the fall, you can harvest through winter and spring, avoiding the worst of the summer heat. Our 355-day growing season gives you plenty of time.

Starting calendula seeds indoors in Florida is an option, but honestly, direct sowing is often easier. If you want a head start, sow seeds indoors from early to late November, about six weeks before you plan to transplant. Use seed trays with a good seed-starting mix, and keep them warm and well-lit.

Bottom watering is a great way to prevent damping-off, a common problem with seedlings. Just set the tray in a shallow dish of water and let the soil absorb it from the bottom. Remember, our spring character is reversed here, so getting a jump start helps you get those blooms before it heats up too much.

Transplant your calendula seedlings outdoors from late December through early February. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Florida sunshine and temperature swings.

Space the plants 8-12 inches apart to allow for good air circulation, which is crucial in our humid climate. Keep an eye on the weather forecast; a cold snap can still happen during this time, so be prepared to cover your seedlings if necessary.

Direct sowing calendula is a simple and effective method in Florida. Sow seeds from late December through early November, taking advantage of our mild winters and long growing season. Choose a spot with full sun to part shade.

Prepare the soil by loosening it and mixing in some compost. Calendula prefers well-drained soil, which is especially important given our sandy soil. Sow the seeds about 1/4 inch deep and keep the soil consistently moist until they germinate. Thin seedlings to 8-12 inches apart once they emerge.

Watering calendula in Florida requires a bit of finesse, especially with our high humidity and distinct wet and dry seasons. During the cooler months (fall, winter, and early spring), water deeply but less frequently, allowing the soil to dry out slightly between waterings. A good rule of thumb is about 1 inch of water per week, either from rainfall or irrigation.

The "finger test" is your best friend: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Avoid overhead watering as much as possible, as our humidity makes plants susceptible to fungal diseases. Water at the base of the plant to keep the foliage dry.

In the summer, calendula may go dormant due to the heat. Reduce watering during this time, but don't let the soil completely dry out. Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to root rot, indicated by yellowing leaves and a mushy stem.

Mulching around your calendula plants with pine straw or wood chips helps retain moisture in the soil and suppress weeds. This is especially helpful in our sandy soil, which tends to dry out quickly.

Pruning calendula is essential for encouraging continuous blooming in your Florida garden. The key is to deadhead regularly, removing spent flowers as soon as they start to fade. This prevents the plant from putting energy into seed production and encourages it to produce more blooms.

Simply snip off the flower heads just below the base of the flower. Leave any healthy foliage intact. Toward the end of the season, around the time of our first frost in late December, you can let some of the flowers mature and develop seeds if you want to save them for next year.

You can expect your first calendula harvest from early February through early January, about 45 days after planting. Harvest the flowers when they are fully open, ideally in the morning after the dew has dried. The petals are most flavorful and have the highest medicinal properties at this stage.

To harvest, simply snip off the flower heads with scissors or pruning shears. Be careful not to damage the surrounding foliage. Calendula is a continuous bloomer, so the more you harvest, the more flowers it will produce.

As our first frost approaches in late December, you can harvest all the remaining flowers and dry them for later use. Alternatively, you can leave some flowers on the plant to self-seed, but be aware that calendula can become quite prolific.

Here are some common problems you might encounter growing calendula in Florida:

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems. Leaves curl, yellow, and die.
• What causes it: Fungi thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it. Our high humidity can make this a recurring issue.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays help. Milk spray (1 part milk to 9 parts water) is surprisingly effective. Plant resistant varieties.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapid-reproducing sap-sucking insects. Populations explode in warm weather. Our warm weather extends their season. Ant colonies may farm them for honeydew.
• How to fix/prevent it: Strong water spray knocks them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer (it attracts them).

Whiteflies

• What it looks like: Tiny white, moth-like insects that fly up when disturbed. Yellowing or silvering leaves. Sticky honeydew.
• What causes it: Sap-sucking insects thrive in warm, humid conditions. Our year-round warm climate allows them to persist.
• How to fix/prevent it: Yellow sticky traps catch adults. Strong water sprays dislodge them. Insecticidal soap or neem oil. Reflective mulch can deter them.

Florida Specific Challenges: Our hot heat, very-high humidity, and wet-summer rainfall create a perfect environment for fungal diseases like powdery mildew. Good air circulation and careful watering are crucial. Nematodes can also be a problem in our sandy soil, so consider soil solarization or using nematode-resistant varieties.

Calendula is a great companion plant for many vegetables in your Florida garden. Plant it near tomatoes and peppers to attract beneficial insects like ladybugs, which prey on aphids and other pests. The calendula acts like a trap crop, drawing the aphids away from your vegetables.

Green beans also benefit from calendula, which can help deter bean beetles. Avoid planting calendula near members of the cabbage family, as it can attract cabbage moths.